Technological Field
The present invention relates to an image forming system that has a function of reading an image on a recording medium to determine the quality of the image, and ejects the recording medium into an ejector including a stacker.
Description of the Related Art
In production printing and the like, a task of checking whether the printed material is in a desired state is common, and in recent years, abnormal image detecting techniques using CCD cameras or the like have been suggested (JP 2015-049189 A, JP 2015-179122 A, and JP 2014-144627 A, for example). In addition to that, there are generally known techniques for switching sheet ejection destinations for a paper sheet from which an abnormality is detected, issuing a warning about the abnormality, indicating the paper sheet to be removed, and the like.
For example, in JP 2015-049189 A and JP 2015-179122 A, control is performed so that a paper sheet determined to have an abnormal image is ejected onto a sheet catch tray for the paper sheets to be discarded. In JP 2015-049189 A, a plurality of recording medium storage units are controlled in accordance with information indicating the ejection destination, so that it is possible to switch to such a state that the recording mediums stored in the respective recording medium storage units can be recovered in order of ejection of the recording mediums. In JP 2015-179122 A, a plurality of sheet catch tray designating units are controlled in order of pages of the paper sheets ejected onto the respective sheet catch trays in accordance with information indicating the sheet ejection destination. Thus, the recovery of the paper sheets from the corresponding sheet catch tray can be facilitated in order of pages.
In JP 2014-144627 A, in a case where a paper sheet is determined to be defective as a result of determination as to whether the paper sheet is defective, the pages including the page determined to be defective and the pages that follow are reprinted, and control is performed so that the paper sheets are ejected into a different sheet ejection destination from the sheet ejection destination used immediately before the defect determination. Thus, wasted paper sheets can be readily removed.
In JP 2017-048019 A, in a machining defective cardboard sheet removing apparatus that automatically removes defective cardboard, a cardboard sheet that has a machining defect and is being conveyed on a belt conveyor is ejected in a different direction from the direction of conveyance, in accordance with a detection signal from a machining defect detector.
Meanwhile, in an image forming system that includes a device (a stacker) having a large-capacity stacking function and a device that detects an abnormal image, printing paper sheets including a paper sheet determined to have an abnormal image (this paper sheet will be hereinafter referred to as a wasted paper sheet) are normally ejected into the stacker.
When the wasted paper sheet in the stacker is removed, it is necessary to cause the elevating tray in the stacker to descend, open the front door of the stacker, and find the wasted paper sheet from among the stacked paper sheets before removing the wasted paper sheet. These operations require a long time and are troublesome. As a result, work efficiency becomes lower.